- [in voiceover] Listen. Can you hear it? The music. I can hear it everywhere. In the wind, in the air, in the light. It's all aound us. All you have to do is open yourself up. All you have to do is listen.
- Richard: Why is it so important that you want him now?
- Lyla: I've ALWAYS wanted him!
- Lyla: [in tears] I've waited eleven years, two months, and fifteen days just to find out that he's alive!
- [Jeffries stares at Lyla]
- Lyla: [she chuckles a little] I've been counting.
- Wizard: What do you want to be in the world? I mean the whole world. What do you want to be? Close your eyes and think about that.
- August Rush: Found.
- Wizard: [pauses] Doesn't have enough yin. Little more yang, ya know?
- August Rush: Yeah.
- Freddie Highmore - Evan Taylor / August Rush
- Keri Russell - Lyla Novacek
- Jonathan Rhys Meyers - Louis Connelly
- Robin Williams - Maxwell "Wizard" Wallace
- Terrence Howard - Counselor Richard Jeffries
- William Sadler - Thomas Novacek
- Marian Seldes - The Dean
- Jamia Simone Nash - Hope
- Mykelti Williamson - Reverend James
- Leon G. Thomas III - Arthur
- Alex O'Loughlin - Marshall Connelly
- Bonnie McKee - Lizzy
- Timothy Mitchum - Joey
- Becki Newton - Jennifer
- Aaron Staton - Nick
- Ronald Guttman - The Professor